JPH0755031B2 - AC power supply - Google Patents

Description

The present invention relates to an uninterruptible power supply device and the like that can supply stable AC output power even when the input AC power supply is momentarily interrupted. The present invention relates to an AC power supply device that can temporarily stop load power supply and retry load power supply when a failure occurs inside the device, depending on the content of the failure.

(Prior Art) There are various types of AC power supply devices of the present invention.
Here, an uninterruptible power supply will be described as a representative example.

The uninterruptible power supply is introduced in Toshiba Review Vol. 42, No. 11 (November, 1987) PP877 to 880, etc., and its function and operation outline are known. Therefore, FIG. 3 is used here. Then, the output voltage control method of the uninterruptible power supply and the problems of the prior art will be mainly described below.

In FIG. 3, 11 is an input AC power supply, 12 is a rectifier, 13 is an inverter, 14 is an inverter transformer, 15 is an output terminal of an uninterruptible power supply, 16 is a battery, 17 is a switch, 18 is a DC filter capacitor, 19 Is an AC filter capacitor, 20 is a voltage reference setter, 21 is an output voltage detection circuit, 22 is a voltage controller, 23 is a frequency controller, 24 is a PWM controller, 25 is a gate amplifier, or 26 is a control circuit power supply, and 27 is An operation stop circuit, 28 is an operation stop command, and 29 is a failure detection circuit. Further, 30 is a fuse and 31 is a circuit component provided for protection.
Is a shunt, 32 is an input voltage detector, 33 is a DC voltage detector,
34 is a blown fuse detector, 35 is a DC overcurrent detector, 36 is an inverter overcurrent detector, 37 is an output overcurrent detector, 38 is an output overvoltage detector, 39 is a battery voltage detector, and 40 is a control power source. It is a loss detector.

With the configuration of the uninterruptible power supply shown in this figure, input AC power supply 11
During normal operation, this is converted to DC power by the rectifier 12 and DC
Smoothing is performed by the filter capacitor 18 and inversely converted into AC power by the inverter 13, and AC power of sine waveform is supplied to the output terminal 15 via the inverter transformer 14 and the AC filter capacitor 19. The voltage of this output AC power is the voltage reference
Vr and the detection signal of the output voltage detection circuit 21 are compared and controlled by the voltage controller 22, and this output signal and the output signal of the frequency controller 23 are compared.
It is controlled by PWM control of the main circuit element of the inverter 13 through the PWM amplifier 24 and the gate amplifier 25, and the output voltage is determined by the voltage reference 20 and the output frequency is determined by the frequency controller 23. .

On the other hand, if the voltage of the input AC power supply 11 falls below 10% of the steady value due to a lightning strike or a ground fault, for example, the power supply from the input AC power supply 11 cannot be continued. When this is detected, the switch 17 is made conductive, and DC power is supplied from the battery 16 via the switch 17. In this way, when the voltage of the input AC power supply 11 drops, power is supplied from the battery 16 so that the inverter 13
Also, a predetermined stabilized AC power can be output to the output terminal 15 via the inverter transformer 14. Generally, the battery 16 can compensate for such a power failure for about 5 to 10 minutes.

Monitor the operation of the uninterruptible power supply that functions as described above,
For protection, the operation stop circuit 27 operates as an uninterruptible power supply according to the operation stop command 28, and also stops the operation by a protection command from the failure detection circuit 29. Protection detection circuit
29 is controlled by the detection signal detected by the protection detector of each part in an uninterruptible power supply. An example of these protection detectors is shown in FIG. An input voltage detector 32 for detecting overvoltage or undervoltage of the input AC power supply 11, a DC voltage detector 33 for detecting overvoltage or undervoltage of the output voltage of the rectifier 12, and a shunt 31 for detecting an input overcurrent of the inverter 13. DC overcurrent detector
35, the fuse 30 for protecting the DC overcurrent, the fuse blowout detector 34, the inverter overcurrent detector 36 for detecting the output overcurrent of the inverter 13, and the output overvoltage detection for detecting the overvoltage of the voltage output from the output terminal 15. Protector of the main circuit such as the device 38, the output overcurrent detector 37 for detecting and protecting the output overcurrent, the battery voltage detector 39 for detecting the voltage drop of the battery 16, and the power loss of the control circuit power supply 26. There are protective detectors, such as the control power loss detector 40 that detects. When these protection detectors detect protection and output a detection signal to give a signal to the failure detection circuit 29, the operation of the uninterruptible power supply is finally stopped regardless of the status of the operation command 28. It was

FIG. 4 shows an example of a power supply system using such an uninterruptible power supply. In this figure, 51 is an uninterruptible power supply, 52 is a load, 53 is an input breaker, 54 is an output switch, 55 is a bypass circuit, and 56 is a switching circuit. Uninterruptible power supply 51
The failure detection circuit 29 in the
Irrespective of the state, when the uninterruptible power supply 51 fails and stops through the operation stop circuit 27, the input breaker 53 is opened, the output switch 54 is commanded by the switching circuit 56, and the input AC power supply 11 bypasses the bus. Power is supplied to the load 52 via the circuit 55. When the load 52 is supplied to the load 52 via the bypass circuit 55 in this manner, the operation of the load 55 can be maintained, but it is not possible to supply the load 52 with high-quality electric power that eliminates the effects of the input AC power supply 11 such as moments and overvoltage. was there.

(Problems to be Solved by the Invention) As described with reference to FIGS. 3 and 4, in the uninterruptible power supply device 51 of the prior art, when the internal failure detection circuit 29 performs the failure protection detection. , The load power supply to the uninterruptible power supply 51 is stopped, and the load power supply cannot be performed until the failure detection circuit 29 is artificially reset (reset after performing a cause investigation and a repair / repair.). There was a problem.

(1) Loads high-quality power for a long time by detecting failure protection.
Cannot be powered.

(2) When failure protection is detected and the uninterruptible power supply 51 shuts down, the load 52 has a very high public impact such as a large computer, which has a very high social impact. Gives great anxiety.

For this reason, there is a need to restore the situation promptly, but since users tend to be decentralized, it will take a long time to recover the cause after the maintenance of the manufacturer arrives.

For this reason, there is a risk that social unrest may occur if the uninterruptible power supply 51 is stopped due to detection of failure protection.

The present invention has been made in view of the above-mentioned drawbacks of the prior art. Even when the AC power supply device detects a failure protection, the power is temporarily fed from the bypass circuit or another AC power supply device to determine the failure content. It is an object of the present invention to provide an AC power supply device capable of automatically resetting a failure detection circuit and continuing load power supply again for a failure due to an external factor.

[Structure of Invention]

(Means for Solving the Problems) As shown in FIG. 1 and FIG. 2 in the embodiment, in the present invention, in an AC power supply device such as an uninterruptible power supply device, a failure detection circuit provided therein fails. When the protection is detected and the device is stopped, the failure detection circuit of the AC power supply unit is automatically reset by the failure determination circuit by determining the failure content detected by the failure detection circuit and the detection level of other protection detectors. If a failure due to an external factor that can be automatically reset is given, the failure determination circuit gives a command to the operation stop circuit or the switching circuit to operate the AC power supply device again to continue the load power supply.

When an internal failure occurs in the AC power supply, the failure determination circuit determines whether the internal failure is an internal failure caused by an external factor of this apparatus or an internal failure caused by an internal factor in the apparatus. If the internal failure occurs, the AC power supply is restarted to restart the load power supply.

(Operation) In the present invention, as shown in FIG. 1 and FIG. 2, in the AC power supply device, when failure protection is detected inside the AC power supply device and operation cannot be continued. ,
The failure detection circuit 29 detects this and temporarily stops the operation of the AC power supply device through the operation stop circuit 27, and the power supply to the load is performed by another power supply, and the failure determination circuit detects a failure due to an external factor of the device. It is possible to determine whether the failure is due to an internal factor, and if the failure is due to an external factor, restart the AC power supply device and continue power supply to the load 52.

FIG. 1 shows a method of temporarily supplying power to the load 52 from the bypass circuit 55 when the failure protection of the uninterruptible power supply 51 is detected. When the uninterruptible power supply 51 is restarted, the load is reloaded. Power is supplied to 52 from the uninterruptible power supply device 51.

Fig. 2 shows the restart of the uninterruptible power supply 51 by the method of supplying power to the load 52 only by another AC power supply (uninterruptible power supply) when the failure protection of the uninterruptible power supply 51 is detected. In this case, the load 52 is again fed in parallel with another AC power supply device by the uninterruptible power supply device 51.

(Example) An example of the present invention is shown in FIG. In this figure, the constituent elements denoted by the same reference numerals as those of FIG. 4 which is an embodiment of the prior art are the constituent elements of the same function, and the description thereof will be omitted. As a component added in FIG. 1 as an embodiment, 56 is a switching circuit, 57
Is a failure determination circuit.

In the embodiment of FIG. 1 of the present invention, when the uninterruptible power supply 51 detects a failure protection, the uninterruptible power supply 51 switches the power supply to the load 52 to the bypass circuit 55 and the failure detection circuit 29. The failure determination circuit 57 determines the failure of the content of the protection detector detected in step 1, and determines whether the failure is caused by an external factor. There are various factors for failure protection of the various protection detectors shown in FIG.

For example, if the blown fuse detector 34 operates,
It is a failure that internal parts 13 are deteriorated, and the control power supply loss detector 40 operates when the control circuit power supply 26 becomes abnormal. The operation of such a protection detector is a failure due to an internal factor of the uninterruptible power supply 51, and an internal failure due to such an internal factor restarts the uninterruptible power supply 51 unless the cause of the failure is removed. Can not do it.

On the other hand, when the DC detector 33 operates, an abnormality of the input AC power supply 11 or a voltage drop of the battery 16 is considered as a failure factor. Whether this factor is detected is the detection level of the input voltage detector 32 or the battery voltage detector 39. It can be judged from the change of. In addition, the inverter overcurrent detector 36 and the DC overcurrent detector
When 35 operates, it is considered that the load 52 actually becomes heavy, and it can be judged from the change of the detection level of the output overcurrent detector 38 whether this is the cause or not. Such an operation of the protection detector is a failure due to an external factor of the uninterruptible power supply 51. Since such a failure due to an external factor does not have a failure factor inside the device, naturally the external factor is eliminated. Then, even if the uninterruptible power supply 51 restarts and supplies power to the load 52,
The restart can be continued.

Whether the fault is caused by such an internal factor or the external factor is detected by the fault discriminating circuit 57 by the fault discriminating circuit 57 to discriminate the detection level of the protective detector or the other protective detector whose fault is detected by the fault detecting circuit 29. For the operation of the protection detector that is determined to be a failure due to the failure detection circuit, the uninterruptible power supply 51 that has been stopped by the operation of the failure detector 29 and the operation stop circuit 27
The load that was restarted through the operation stop circuit 27 and the switching circuit 56 by the action of 57 and was switched to the power supply to the bypass circuit 55.
The power supply to 52 is switched again to the power supply from the uninterruptible power supply device 51, and the power supply from the uninterruptible power supply device 51 is continued again.

Whether or not the failure is caused by an external factor described in the present invention depends on the detection level of the protection detector of each part provided inside the uninterruptible power supply 51 and the protection detector that has detected the failure, or the mutual operation of the protection detector that has detected the failure. It can be determined by the failure determination circuit 57 depending on the situation.

As described above, according to the embodiment of the present invention, when the uninterruptible power supply detects a failure, the power supply to the load is temporarily switched to the bypass circuit side, but the failure determination circuit determines that the failure is caused by an external factor. In this case, the load power supply from the uninterruptible power supply can be restarted. In general, failures of uninterruptible power supply are often caused by external factors, so in many cases it is possible to perform load power supply from the uninterruptible power supply, and to supply high-quality power for a long time as originally intended. It is obvious that the reliability of the power supply can be improved.

Another embodiment of the present invention is shown in FIG. In this figure, 58 is an output breaker, 59 is an uninterruptible power supply, 60 is an input breaker, and 61 is an output breaker. In this configuration, normally input breakers 53 and 60, output breaker 58
And 61 are closed and the uninterruptible power supplies 51 and 59 are operated to supply power to the load 52. When an internal failure occurs in the uninterruptible power supply device 51 as in FIG. 1, the power supply from the uninterruptible power supply device 51 to the load 52 is stopped. However, if the internal failure is due to an external factor, the power supply from the uninterruptible power supply unit 51 to the load 52 is restarted as in the embodiment of FIG. Even if the uninterruptible power supply unit 51 fails and stops, the power supply with higher quality than the uninterruptible power supply unit 59 continues, but when the supply of power from the uninterruptible power supply unit 51 to the load 52 is restarted, the redundancy of the power supply increases. , It is clear that the reliability of the power supply is improved.

It is obvious that the present invention can be applied not only to the uninterruptible power supply device but also to an AC power supply device that does not have the battery 16 in FIG. The configuration is not particularly limited.

In addition, it is obvious that various modifications can be configured within the scope of the present invention.

〔The invention's effect〕

According to the present invention, even if an internal failure occurs in an AC power supply such as an uninterruptible power supply, most of the internal failure is often due to external factors. It can be started up and the load power can be continuously supplied again. As a result, it is clear that an AC power supply device having the following effects can be realized by the present invention.

(1) The purpose of supplying high-quality electric power to the load, which is the original purpose of providing the AC power supply device, can be achieved more than in the related art.

(2) Since the failure of the AC power supply device for a long period of time is greatly reduced as in the conventional case, the reliability of the power supply is significantly improved, and social unrest and confusion associated with the failure stop can be prevented.

[Brief description of drawings]

1 and 2 are block diagrams showing different embodiments of the present invention, and FIGS. 3 and 4 are block diagrams showing the configuration of a conventional AC power supply device (uninterruptible power supply device). 11 …… input AC power supply, 12 …… rectifier, 13 …… inverter, 14 …… inverter transformer, 15 …… output terminal, 16 …… battery, 17 …… switch, 18 …… DC filter capacitor, 19 …… AC filter capacitor, 20 …… voltage reference, 21 …… output voltage detector, 22 …… voltage controller, 23 …… output frequency controller, 24 …… PWM controller, 25 …… gate amplifier, 26 …… control Circuit power supply, 27 ... Operation stop circuit, 28 ... Operation stop command, 29 ... Failure detection circuit, 30 ... Fuse, 31 ... Shunt, 32 ... Input voltage detector, 33 ... DC voltage detector , 34 …… Fuse blown detector, 35 …… DC overcurrent detector, 36 …… Inverter overcurrent detector, 37 …… Output overcurrent detector, 38 …… Output overvoltage detector, 39 …… Battery voltage detection Input device, 40 …… control power loss detector, 51 …… uninterruptible power supply, 52 …… load, 53 …… Circuit breaker, 54 ... Output switcher, 55 ... Bypass circuit, 56 ... Switching circuit, 57 ... Fault determination circuit, 58 ... Output breaker, 59 ... Uninterruptible power supply, 60 ... Input breaker , 61 …… Output breaker.

Claims (2)

[Claims] 1. At least one AC power supply is composed of an uninterruptible power supply device for converting AC power supplied from an input AC power supply into stabilized AC power, and the other AC power supply is obtained from the input AC power supply. In the AC power supply device that is configured by the AC power supply of No. 1 and can supply power to any load from any AC power supply by a switch, if a failure occurs while power is being supplied to the load by one of the AC power supplies, Switching means for stopping the operation and temporarily supplying power to the load from the other AC power supply side, and a failure for detecting a failure of an element that is provided inside the uninterruptible power supply and constitutes the uninterruptible power supply Detecting means, failure determining means for determining whether the failure is an internal factor due to deterioration of the element or abnormal control power supply, based on the detection result from the failure detecting means, and the failure determining means AC power supply comprising means for restarting the one AC power supply and switching the power supply to the load to the one AC power supply side again when it is determined by the stage that the failure is not due to an internal factor. apparatus. 2. An AC power supply device comprising at least two uninterruptible power supply devices that are connected in parallel and supply stable AC power to a load, when a failure occurs in one of the uninterruptible power supply devices, Means for stopping the operation of the failed uninterruptible power supply and temporarily disconnecting it from the load power supply, and failure detection means for detecting a failure of an element which is provided inside the uninterruptible power supply and constitutes the uninterruptible power supply And a failure determination means for determining whether the failure is an internal factor due to deterioration of the element or control power supply abnormality based on the detection result from the failure detection means, and the failure determination means causes the failure to be an internal factor. The AC power supply device comprising means for restarting the uninterruptible power supply device and again operating in parallel with the uninterruptible power supply device on the healthy side when it is determined that the uninterruptible power supply device is not due to the above.